High-sensitivity distributed dynamic strain sensing by combining Rayleigh and Brillouin scattering

Ben Zhang Wang, De Xin Ba, Qi Chu, Li Qiang Qiu, Deng Wang Zhou, Yong Kang Dong

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

The phase-sensitive optical time-domain reflectometry (φ-OTDR) is a good candidate for distributed dynamic strain sensing, due to its high sensitivity and fast measurement, which has already been widely used in intrusion monitoring, geophysical exploration, etc. For the frequency scanning based φ-OTDR, the phase change manifests itself as a shift of the intensity distribution. The correlation between the reference and measured spectra is employed for relative strain demodulation, which has imposed the continuous measurement for the absolute strain demodulation. Fortunately, the Brillouin optical time domain analysis (BOTDA) allows for the absolute strain demodulation with only one measurement. In this work, the combination of the φ-OTDR and BOTDA has been proposed and demonstrated by using the same set of frequency-scanning optical pulses, and the frequency-agile technique is also introduced for fast measurements. A 9.9 Hz vibration with a strain range of 500 nε has been measured under two different absolute strains (296.7µε and 554.8 µε) by integrating the Rayleigh and Brillouin information. The sub-micro strain vibration is demonstrated by the φ-OTDR signal with a high sensitivity of 6.8 nε, while the absolute strain is measured by the BOTDA signal with an accuracy of 5.4 µε. The proposed sensor allows for dynamic absolute strain measurements with a high sensitivity, thus opening a door for new possibilities which are yet to be explored.

Original languageEnglish
Article number200013
Pages (from-to)1-8
Number of pages8
JournalOpto-Electronic Advances
Volume3
Issue number12
DOIs
StatePublished - 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2019 Institute of Optics and Electronics, Chinese Academy of Sciences.

Funding

This work was supported by the National Key Scientific Instrument and Equipment Development Project of China (2017YFF0108700) and National Natural Science Foundation of China (61975045). The authors would like to express our gratitude to Long Wang, Chao Pang and Yabo Feng for their help in the experiment.

FundersFunder number
National Natural Science Foundation of China61975045
National Key Scientific Instrument and Equipment Development Projects of China2017YFF0108700

    Keywords

    • Brillouin scattering
    • Fast measurement
    • Fiber optics sensor
    • Rayleigh scattering

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